Adding a 7.2kV load on a 4.16kV system
Adding a 7.2kV load on a 4.16kV system
(OP)
We have a 4.16kV LRG system here at our plant.
There is a new piece of equipment which others are considering adding that will operate at 7.2kV. I am told tha this equipment will have a peak demand of 1198kW and an average demand of 696kW. In order to operate this machinary at 7.2kV we will have to obviously install a 4.16kV to 7.2kV step-up transformer somewhere on our system. I am trying to take a preliminary look at some circuits to determine if we have the capacity for adding this transformer and picece of equipment.
Is there anything I should watch our for when looking at circuit capacity for adding this step-up transformer and equipment load. I know the step-up transformer may need to be somewhat oversized due to starting effects with the 7.2kV equipment load. Is there a typical value for oversizing this transformer that I can use to gauge capacity?
Is there anyting to watch out for in regards to this transformer being fed from a LRG system? Other than cable insulation rating?
I'd appreciate any insights or comments on this as we are in the process of doing some preliminary reviewing.






RE: Adding a 7.2kV load on a 4.16kV system
Alan
Democracy is two wolves and a sheep deciding what to have for dinner. Liberty is a well armed sheep!
Ben Franklin
RE: Adding a 7.2kV load on a 4.16kV system
From what I am told the load consists of two Gen-Sets which use synchronous motors. Therefore I'm not sure that power factor would play a major issue in determining the size of the transformer.
I am not sure about the duration of the peak loading, I will have to find out.
We already have a circuit which a 100hp motor. This new additional load at 1198 kw would be about a 1600hp motor equivelent. We may be able to beef up our existing circuit to accomidate this new transforemr and equipment.
Others are arguing with me that we do not have the capacity on this cirucit and will need to tap another feed off of our utility transformer.
RE: Adding a 7.2kV load on a 4.16kV system
you should look at the voltage drop everywhere on your system, specially when the motor will be started. Could be a problem.
RE: Adding a 7.2kV load on a 4.16kV system
RE: Adding a 7.2kV load on a 4.16kV system
I'm trying to get more information on the loads, such as exactly what size motor are used.